Resinous interpolymers containing 1, 2-dicyano-1-chloroethylene



. plication.

PM; Aug. 24, 1948 UNITED STATES PATENT OFFICE 2,441,:11 nasmous m'raarovnmns costume LZ-DICYANO-l-CHLOROETHYLENE David T. Mowry, Dayton, Ohio. I to Mon- I I canto Chemical Company, St. Lo Mo.. a corporation of Delaware v No Drawing. Application July 24, 1944, Serial No. 545,432

6 Claims. (Oi. zoo-rat) l The present invention relates to the production of resinous material by the copolymerlzatlon of CH22C substituted aromatic hydrocarbons and 1,2-dicyano-l-chloroethylene.

An object of the present invention is to provide resinous copolymerization products of v substituted aromatic hydrocarbons such as styrene, alpha-methylstyrene and alpha, para-dimethylstyrene. together with 1,2-dicyano-1-chloroethylene. which products have im roved p ysical strength characteristics as well as a higher thermal stability (heat distortion point) than does the polymerized vinyl aromatic hydrocarbon itself.

I have found that valuable interpolymerization products may be obtained by po ymerizing a mixture containing 1.2-dicyano-l-chloroethylene and a CH2=C substituted aromatic hydrocarbon such as styrene, alpha-methylstyrene or alpha, para-dimethyl-styrene. If desired, mixtures .of the latter three hydrocarbons may also be'employed.

1,2-dicyano-1-chloroethylene may be prepared by the action of PzOs on chlorofumaramide as disclosed in a copending application Serial No. 481,584, filed April 2, 1943, now abandoned, by

David T. Mowry and Mary W. Renoll, and assigned to the same asslgnee as the present ap- Polymerization of the above-mentioned compounds to form interpolymers may be carried out by merely heating a mixture of nitrile and the CH2=C substituted aromatic hydrocarbon in mass, in solution or in emulsion. The temperature of polymerization may range from C. to

120 0., although in some cases a higher temperature may be satisfactorily employed.

When carrying out a mass polymerization of the above-mentioned ingredients, a mixture is first prepared by dissolving the nitrile in the liquid monomeric CH2=C substituted aromatic hydrocarbon, after which the mixture is subjected to polymerizing conditions by the application of heat either in the absence or in the presence of a polymerization catalyst. The latter may be benzoyl peroxide, acetyl peroxide or any other of the known catalysts of polymerization. For most satisfactory operation the mixture should contain from 0.5% to 50% by weight of dinitrile, although interpolymerization will occur even with greater amounts of dinitrile present,-the excess of dinitrile being readily recoverable in unpolymerized form.

The amount of1,2-dicyano-l-chloroethylene combined as interpolymer may vary from 1% to 50% by weight of interpolymer, the amount used being dependent upon the physical characteristics of the interpolymer desired. In general, it may be said that the greater the amount of nitrile employed, the higher will be the thermal softening point or heat distortion point.

1,2-dicyano-1-chloroethylene is selective in respect to its copolymerizing properties. It exhibits no tendency to interpolymerize with a great many vinyl compounds such as vinyl chloride, vinyl esters such as vinyl acetate or vinyl ethers.

' The present interpolymers may be readily obtained in a clear, transparent and chemically stable form. The present products may be employed for the production of transparent objects such as interlayers for safety glass and the like, for the manufacture of transparent-molded articles, for electrical insulating materials, etc.

Although the 1,2-dicyan'o-l-chloroethylene does not itself polymerize, I have found that in the presence of a CH2=C substituted aromatic hydrocarbon it tends to accelerate rather than inhibit the copolymerizing reaction, 1. e., mixtures of the above dinitrile and polystyrene tend to polymerize faster than does styrene itself. Accordingly, should it be desirable, lower temperatures may advantageously-be employed for the polymerization of the herein-described mixtures. Mixtures of styrene and 1,2-dicyano-1-chloroethylene are most advantageously polymerizedin mass at temperatures below about C.,'-although, if desired, higher temperatures up to, say, C. may be employed. However, because of the accelerating effect of the dinitrile upon the polymerization reaction, polymerizing temperatures in the neighborhood of from 50- C. to 80 C. may be usefully employed, depending upon the rate of polymerization desired. In general,

higher temperatures promote a faster polymer- 3 cyano-I-chloroethylene during its polymerization with the CHa=C substituted aromatic compound I may employ the polymerization process disclosed in the copending application of Reid G. Fordyce, Serial No. 503,941, filed September 27, 1943, now abandoned, which application is assigned to the same assignee as thepresent application.

For the production of clear, transparent, resinous products derived from monomeric styrene, I may employ mixtures of monomeric styrene and 1,2-dicyano-l-chloroethylene, inwhich mixtures the nitrile content is below approximately 50% by weight and preferably below 35% by weight of said mixture. During polymerization by mass or solution methods, and depending upon the relative proportions of the dinitrileand the CH2=C substituted aromatic hydrocarbon present in the mixture undergoing polymerization, one of the constituents thereof will enter the growing polymer chain at a greater rate than the other constituent. It may, accordingly, be desirable during polymerization to maintain constant concentration of the constituent which enters the copolymer at the highest rate. This may be done as described in the above-mentioned application Serial No. 503,941 by a determination of the concentration of the respective monomers and copolymer present and then adjusting the concentration of the monomeric mixture to that originally present in the mixture.

The polymerization of mixtures of the CHz=C substituted aromatic hydrocarbon with the dinitrile, if desired, may be carried to completion, 1. e., carried to'the stage where a hard, solid, resinous material is obtained which is substantially free from monomeric material. Such a method. is useful when producing cast objects. For most purposes, however, the polymerization is generally carried to a degree which is short of complete polymerization and the interpolymer thereafter recovered by solution in a solvent such as benzol or dioxane, which solution is then poured into a lower aliphatic alcohol wherein the interpolymer is insoluble and in which the unpolymerized monomeric materials still present are soluble. Such a procedure results in the production of a finely divided powdery to fibrous, colorless to slightly yellowish material which may be washed free of adhering monomeric materials and solvents and then dried. The material is then suitable for use as a molding powder.

The invention is further illustrated by means of the following examples which are given for the purpose of illustration and are not to be considered as limitations upon the present invention.

Example 1 the resinous materialby solution in dioxane fol-v lowed -by precipitation of the copolymer in alcohol.

The interpolymer is soluble in dioxane, ethyl acetate, acetone, ethylene dichloride and in 2-nitropropane. It is insoluble in ethyl alcohol, gasoline and carbon tetrachloride. It softens in benzene.

The powdery material thus obtained had a softening point of 170 C. and a melting point of 215 C. It'may be molded by compression molding in the heated die and will be found to have an ASTM heat distortion point substantially higher than that of polystyrene.

In place of styrene, alpha-methylstyrene or alpha, para-dimethylstyrene, or mixtures thereof with styrene, may be employed.

' Example 2 A monomeric mixture of styrene and 1,2-dicyano-l-chloroethylene, said mixture containing approximately 2.5% by weight of dinitrile, is polymerized by heating in the presence of a polymerization catalyst to a temperature of C. to 60 C. with stirring. During the polymerization, samples of the mixture are withdrawn and the content of copolymer in the mixture determined by precipitation in alcohol. The content of the dinitrile in the copolymer may be determined by analysis of its nitrogen content. Based upon the analysis the amount and composition of the copolymer may be determined as well as the concentration of the dinitrile in the monomeric mixture. As a result of such an analysis, the amount of interpolymer present, as well as the composition of the interpolymer and the monomeric mixture containing the same, may be evaluated. Based upon such a determination the monomeric mixture may be adjusted to that originally present and the composition of the copolymer with respect to dinitrile maintained at a substantially constant value throughout the polymerization.

When polymerizations are carried out as above described, 1. e., in the absence of a solvent, the degree of polymerization may be carried to the point where the mixture contains between, say, 20% and 30% by weight of the interpolymer. At this point the viscosity of the mixture ordinarily becomes too high for the maintenance of uniformity and the polymerization may be interrupted and the interpolymer recovered by solution in a solvent followed by precipitation by addition of a mixture to alcohol.

If desired, the polymerization may be carried out in solution in a solvent such as dioxane, in which case the polymerization may be carried to a greater content of copolymer than was possible in the absence of a solvent. By the use of suitable amounts of solvents the extent of polymerization may be carried t060% to 70% of completion. Polymeric material is recovered by precipitation in alcohol. In this manner a moldable interpolymer which is clear and homogeneous may be obtained.

The behavior towards solvents of the resinous interpolymer depends upon the amount of copolymerized 1,2-dicyano-l-chloroethylene contained therein. In general, the resistance of the interpolymer towards solvents increases with the content of the dinitrile.

The interpolymerization of the vinyl aromatic compound and 1,2-dicyano-l-chloroethylene may also be carried out in the presence of plasticizers and plasticized resinous bodies obtained.

Example 3 A mixture comprising '70 g. of styrene. 30 g. of

1,2-dicyano-l-chloroethylene and 30 g. of butyl phthalyl butyl glycollate is polymerized by heating at a temperature of 80 C. for days and then at 120 C. for one day. The resulting hard, clear resin is ground to a powder and then milled on heated rolls. If desired, coloring matter may be added, while milling. The milled material is then reduced to a powder and may be molded in heated dies for the production of various objects.

Various other proportions 01 a CH2=C substituted aromatic compound and 1,2-dicyano-1- chloroethyiene may also be employed in the presence of plasticizers. Other plasticizers such as tricresyl or triphenyl phosphate may also be employed in a similar manner.

Example 4 A mixture consisting of 85 g. of monomeric styrene and 15 g. of 1,2-dicyano-1-chloroethyiene is emulsified to a fine milk in 120 g. or water containing 3 g. of disodium phosphate. 0.8 g. of citric acid and 0.04 g. of potassium persuliate and also containing 12.4 g. of sodium lorol sulfate as' an emulsifying agent. The pH of emulsion is about 5.0. The emulsion is polymerized by refluxing (boiling under a reflux condenser for 15 minutes). The emulsion is then broken by pouring 1 into tween 0.5% and 50% by weight of said 1',2-dicyano-l-chioroethylene the balance thereof being said CH2=C substituted aromatic hydrocarbon and then heating said mixture to a polymerizing temperature to form an interpolymer.

izing temperature to form an interpolymer.

methyl alcohol and the precipitated polymer is filtered. washed with alcohol and water and then dried. Alternatively the emulsion may be broken by adding a solution of an electrolyte.

The dried; finely divided polymer may then be used directly as a molding powder or it may be milled on heated rolls, the sheet thus obtained eomminuted and employed in hot molding operations. The herein-described interpolymers'are resistant to acids and alkalies, i. e., there is no tendency of the nitrile groups in the interpolymer to hydroiyze. The present products are insoluble in dilute or concentrated acids and dilute or concentrated aqueous alkalies. They are free from carboxygroups and also salt groups.

This application is a continuation-in-part of my copending application Serial No. 450,514. died July 11, 1942, now abandoned.

What I claim is:

1. The process which comprises forming a polymerizable mixture of a CHa:C substituted aromatic hydrocarbon selected from the group conslsting 0f styrene, alpha-methylstyrene and alpha,

paradimethylstyrene, together with LZ-dicyanr 3. A resinous material comprising an interpolymer consisting of styrene copolymerized with 1,2-dicyano-l-chloroethylene, said interpolymer containing 15% of copolymerized 1,2-dicyano-1- chloroethyiene.

4. A resinous material comprising an interpolymer consisting of a CH2=C substituted aromatic hydrocarbon selected fro'm the group consisting of styrene, alpha-methylstyrene and alpha,

para-dimethyls'tyrene copolymerized with 1,2-

dicyano-l-chloroethylene, said interpolymer containing between 1.0% and of copolymerized 1.2-dicyano-i-chloroethylene.

5. A resinous material comprising an interpolymer consisting of styrene copolymerized with 1,2-

dicyano-l-chloroethylene, said interpolymer con taining between 10% and 50% by weight of copolymerized 1,2-dicyano-l-chloroethylene.

6. A resinous material comprising an interpolymer consisting of styrene copolymerized with 1,2- dicyano-l-chloroethylene, said interpolymer containing between 5.0% and 35% or copolymerized 1,2-dicyano-l-chloroethylene,

' DAVID T. MOWRY.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED s'ra'rns PATENTS Number Name Date 1,683,402 Ostromislensky Sept. 4, 1928 FOREIGN PATENTS Number Country Date 814,003 France Mar. 8, 1037 6 1'-chioroethylehe, said mixture containing be- 

